Telephone-exchange system.



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPIZICATION men 050.21. 1915.

Patented May 29,1911

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO VJES'IERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

nseasse.

Specification of Letters Patent.

Patented May 29, 191?.

Application filed December 27, 1915. Serial No. 68,820.

To all whom it may concern:

Be it known that I, HENRY P. GLAUSEN, a citizen of the United States, residing at Mount Vernon, in the county of VVestchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems its object being to provide improved signaling means for such systems which will materially reduce the amount of time required for an operator to handle calls for lines which are found busy, thereby bettering the service generally.

This invention, in its broader aspect, embraces a system 1n wh ch a s gnalingdevlce operates to furnish a disconnect signal to the operator after the usual busy signal has been transmitted to the calling subscriber for a predetermined period.

In accordance with this invention, certain jacks on a telephone switchboard equipped with apparatus for furnishing characteristic busy indications and commonly known as busy back jacks, are associated with apparatus for causing a signaling device in a link circuit to furnish a characteristic signal at the expiration of a predetermined period after the link' circuit is connected with a busy back jack. A slow-operating circuit-controlling device associated with each busy back jack operates upon the connection of the link circuit with a jack, and controls the operation of the signaling device. Since the circuit-controlling deviceis slow operating, it delays the operation of the signaling device for a predetermined period after the link circuit is connected with the jack. By this method, when the signaling device operates, the signal produced thereby may be considered as a disconnect signal.

This invention will be more particularly described by reference to the accompanying drawing in which Figure 1 illustrates the invention appliedto the handling of a telephone call from one operator to another through the medium of an intermediate trunk circuit. Fig. 2 shows a modified portion of the busy back circuit and the association therewith of an A oper'ators cord circuit for handling calls local to the fA operators position. Fig. 3 shows another modification of a portion of the busy back circuit. In Fig. 1 is shown a central-energy subscribers line and switchboard equipment at 1. At 2 is indicated an A operators cord circuit for interconnecting subscribers lines; and 3 indicates a trunk circuit terminating at a B operators position l, at which is located a busy back circuit equipment 5 suitable for practising the features of this invention.

In describing the operation of the system shown in Fig. 1, letit be assumed that a subscriber at the station 1 seeks a connection with another. subscriber whose line (not shown) terminates on a switchboard at which the B operators position 4; is lo cated. And let it be further assumed that the line of the subscriber wanted is already connected with the line of another subat station 1. The A operator at 2 transmits a request for completion of the connection to the B operator at 4, by means of telephone sets and an order-wire circuit (not shown). In response to this request, the B operator assigns, say, the trunk circuit 3 to be used in completing this connection, whereupon the A operator inserts a calling plug 8 in the trunk jack 9, The B operator makes the usual busy test by touching the tip of the trunk plug 10 to the jack-shell of the subscribers line wanted (not shown), and upon receiving a. busy test indication, in a well-known way, inserts the plug 10 in a busy back jack 11. A tone current produced in the primary circuit 12 of a transformer 13 by the action of an interrupter wheel 14, induces characteristic currents in the sec ondary windings 15 and 16. As the plugs 6 andS are seated in the jacks 7 and 9, respec: tively, the tone currents present in the secondary windings 15 and 16 traverse the circuits thus connected and produce oorresponding tone sounds in the subscribers receiver at station 1. A connection through the signal-circuit contacts of the plug 10 and the busy back jack 11 permit current from the battery 20 to complete a circuit through the operating winding of a dash-pot relay 21. On the lapse of a predetermined interval of time, a solenoidal plunger of this relay will have moved sufliciently to close the co11- tacts 22 to form a shunt on a resistance unit 23. Shunting of the resistance 23 permits a greater quantity of current to flow from battery through a supervisory relay 24, the winding 15 of the transformer 13 and the interrupter wheel 17 to earth, thereby efl'ecting the operation of this supervisory relay. The resulting alternate energization and deenergization of the supervisory relay 24, in response to the interruptions of this circuit at the wheel 17 sets up, through the corresponding opening and closing of the con-- tacts 25 of thisrelay, similar changes of current action in the conductors of the trunk circuit 3 and the calling end of the link circuit at 2, due to the presence of a battery 30 included in this metallic circuit. A supervisory relay 31 responds to these current changes, and through its contacts 32 intermittently connects and disconnects a resistance unit 33 in parallel with a supervisory lamp 34, thereby causing this lamp to be flashed in a characteristic manner. The circuit of the supervisory lamp 34 is completed through a resistance 35, signal-circuit contacts of the plug 8 and the jack 9, and the resistance unit 36 to earth. On observing this busy back flashing of the supervisory lamp 34, the operator at 2 immediately takes down the connection. This peremptory dis connect operation is permissible owing to the fact that during the time required for the dash-pot relay 21 to close its contacts 22, to thereby initiate the flashing operations of the supervisory lamp 34, a busy tone signal will have been present in the telephone receiver at the station 1 for a period of time sufficient to render the significance of this tone, as indicating the busy condition of the line wanted, to be clearly understood by the waiting subscriber.

During the time the contacts 22 of the dash-pot relay 21 are separated, the relatively high resistance value of the resistance unit 23 prevents a suflicient amount of current through this circuit to operate the supervisory relay 24.

Fig. 2 shows a modified portion of the busy back equipment 5 located at an A operators position, a portion of whose cord circuit is shown at 2. In this figure, a condenser 23 and a thermal relay 21 are shown in place of the resistance 23 and dash-pot relay 21 of Fig. 1. The operation of this equipment is such that when plug 8 is inserted in jack 11, thermal relay 21 delays the closing of contacts 22 for a predetermined interval of time. The closure of contacts 22 permits current from the battery 30, to flow through the supervisory relay 31, winding 15 of the transformer 13, and the interrupter wheel 17 to earth. The periodic interruption of this circuit by interrupter wheel 17 causes the alternate energization and deenergization of supervisory relay 31 and consequent flashing of lamp 34 in the same manner as described in Fig. 1.

It will be understood that the resistance pensed with as shown in Fig. 3 and this circuit allowed to remain open at that point until closed by the contacts 22 of the relay; or a condenser 23 as shown in Fig. 2 may be substituted for this resistance unit. And further, a thermal relay 21 as shown in Fig. 2 or any suitable form of mechanically retarded circuit-controlling device 21" of Fig. 3 may be substituted for the dash-pot relay 21 of Fig. 1 without departing from the spirit of this invention.

What is claimed is:

1. In a telephone exchange system, a' link circuit, a signaling device, a busy back circuit, a source of current for said busy back circuit, a circuit-interrupting means for said busy back circuit to interrupt the circuit of an included link circuit, and a retarder circuit-controlling means for controlling the operative association of said circuit-interrupting means and said signaling device when the link circuit is included with the busy back circuit.

2. In a telephone exchange system, a link circuit, a signaling device, a busy back circuit including a source of signaling current, an interrupter, and a slow-operating relay operating upon connection of the link circuit with the busy back circuit to operatively associate, after a predetermined time, the interrupter and the signaling device.

3. In a telephone exchange system, a link circuit, a signaling device, a busy back circuit including a source of signaling current, apparatus in the busy back circuit for con trolling the operation of said signaling device, and a slow-operating relay operating upon connection of the link circuit with the busy back circuit to operatively associate, after a predetermined time, said apparatus and said signaling device. I

4. In a telephone exchange system, a link circuit, a signaling device, a relay in the link circuit controlling the operation thereof, a busy back circuit including a source of signaling current, an interrupter, and a slowoperating relay operating upon connection of the link circuit with the busy back circuit to operatively associate, after a predetermined time, the signal-controlling relay and the interrupter to cause the signaling device to furnish a characteristic signal.

5. In a telephone exchange system, a link circuit, a signaling device, a busy back circuit including a source of signaling current, an interrupter associated with the busy back circuit for controlling the operation of the signaling device, means associated with the busy back circuit preventing the operative association of the interrupter. and the signaling device upon the connection of the link circuit with the busy back circuit, and a slow-operating relay operating upon such connection to operatively associate the in- 'terrupter and the signaling device after a ated after a link circuit has remained inpredetermined time. eluded With said busy back circuit for a 6. In a busy back circuit, a source of tone predetermined interval of time to operasignaling current a normally ineffective cirtively associate the circuitinterrupting '5 wit-interrupting means, link circuits of a means and the signaling device. 15 telephone switching system accessible to said In Witness whereof, I hereunto subscribe busy back circuit, a signaling device, means my name this 22nd day of December, A. D., for including said link circuits with said busy 1915.

back circuit, and a retarder circuit-control- 10 ling means for said busy back circuit oper- HENRY P. OLAUSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

